This invention relates to bag handling machines of the type including a hopper from which particulate material is dispensed in predetermined quantities or batches through a spout having a discharge end on which a bag is hung for filling. Such bag filling apparatus normally includes clamps carried on the spout movable to a clamping position to hold a bag during the filling operation. See, for example, U.S. Pat. No. 4,078,358.
It is also known to utilize pivotal stretcher arms to elongate the mouth of a bag upon filling; and prior art bag filling machines have included flat rods or bars swingable against the front and back faces of a bag to assist in flattening and closing a bag neck after filling. Such features are disclosed in the aforesaid U.S. Pat. No. 4,078,358 as well as in U.S. Pat. Nos. 2,732,988 and 3,896,605. The latter patent also discloses a pivotal guide rod movable into a horizontal position to assist in supporting a filled bag against a fixed member as the bag is conveyed to a bag closing device. Reference is also made to U.S. Pat. No. 3,889,449 which discloses the distension of a bag while on a filling spout to separate the front and rear edges of the bag for entry of an air blast.
Although previously known and used bag filling machines have been satisfactory to a degree in the filling of bags with particulate material and in the handling of such bags in their movement to a bag closing station, there are no known prior bag filling and handling machines which completely satisfactorily form and hold a bag neck during and immediately after filling on a filling spout and thereafter hold the bag neck in a flattened, properly formed position for presentation to a bag closing device. This is particularly true with respect to the filling of gusseted bags, and prior art bag filling and handling machines are lacking in the provision of means for providing totally controlled handling of filled gusseted bags from the time of pickup to the time when it is introduced at the input side of a bag closing machine, such as a sewing machine. In particular, pinch bottom bags require a great deal of precision in handling to form a seal having the requisite integrity.